The Samsung Messaging has been EXTREMILY BUGGY with RCS / Advanced Messaging on T-Mobile ever since purchase:

1. Scheduled Messages are sent prematurely2. Scheduled text Messages end up in WRONG threads3. Messaging incorrectly displays scheduled messages as "sent" when, in fact, the other party has not received them.4. Duplicate messages sent.5. Images over 3gb only go about 50% of the time.

All of these errors are new since RCS Messaging was enabled and occurs with the SCHEDULED TEXT feature.

If the issue is just occurring with the scheduled messages, I would go into your date and time settings if it is not set to Auto I would set it to Auto. If it is set to Auto, I would set it Manually, then Manually input the date and time, and then set it back to Auto.

I should clarify that the issue was present ever since purchasing the S9+ on 5/23. I have downloaded 2 software updates since then.

I can tie it to the introduction of RCS / advanced messaging however since:

*It did not happen on my S7 edge.*RCS messages do not show up in third party messaging programs like Textra and those are the messages affected.*It does not happen with 3rd party messaging apps like Textra.